1. Field of the Invention
The present invention relates to a reticle-processing system in which transfer means transfers a reticle-carrying container storing a reticle from a reticle stocker to a light exposure apparatus and the light exposure apparatus prints a circuit pattern onto a substrate through the use of the reticle.
2. Description of the Background Art
Semiconductor devices and liquid crystal display devices are manufactured in the process of photolithography. In this process, an image of pattern formed on the reticle (including a photo mask) is projected and transferred by a light exposure apparatus onto a substrate such as a semiconductor wafer and a glass plate.
At that time, the projected pattern reacts with a photosensitive agent applied to the substrate, and then a circuit is formed through the subsequent operations.
During this process, the reticle is handled to be stored in a dedicated reticle-carrying container in order to prevent contamination with dust, etc. and damage from contact with other components.
For making an intricate circuit, it is necessary to provide a large number of circuit patterns on the substrate. Accordingly, many reticles are prepared and many patterns are exposed in layers on the substrate.
FIG. 2 shows one example of a reticle-processing system used in the photolithography process. In the figure, a numeral number 1 indicates a light exposure apparatus that projects and transfers a circuit pattern onto the substrate. A numeral number 2 denotes a reticle stocker in which a large number of reticles are stored and retained. A numeral number 3 shows a reticle-carrying container which stores reticles. A numeral number 4 indicates a transfer rail provided between the light exposure apparatus 1 and the reticle stocker 2, which transfers the reticles stored in the reticle-carrying container 3 between these two components. A numeral number 5 shows a transfer mechanism provided on the transfer rail 4, which holds and transfers directly the reticle-carrying container 3.
These components are controlled by a controller (not shown). With this, the reticles required for a circuit pattern stored in the reticle-carrying container 3 are transferred on the transfer rail 4 by the transfer mechanism 5 from the reticle stocker 2 to the light exposure apparatus 1. The reticles no longer required in the light exposure apparatus 1 are returned to the reticle stocker 2 by the transfer mechanism 5 on the transfer rail 4.
If the reticles used in the above described process are contaminated with dust, etc. or damaged by contact with other components, it is impossible to form an accurate circuit pattern. Therefore, for supporting the reticles safely and securely, they are stored in the reticle-carrying containers 3. The reticle-carrying container 3 is transferred in a state that its orientation is accurately controlled in relation to the circuit pattern printed onto the substrate through light exposure. Such operations as the transfer of the reticle-carrying container 3 and light exposure by means of the reticle are carried out by the reticle-processing system.
One example of the reticle-processing system is shown in Japanese Patent Laid-open No. 10-163094. According to Japanese Patent Laid-open No. 10-163094, a reticle case alignment device is provided so as to perform light exposure with alignment of a reticle case.
Under the above mentioned conventional reticle-processing system, if the operator tries to set the reticle-carrying container 3 from outside in wrong orientation into the reticle-processing system, the setting of the reticle-carrying container 3 is disabled or the operation of the alignment device is stopped. That is, generally, the reticle-carrying container 3 can be set in the system only when the reticle-carrying container 3 is placed in the proper orientation by means of the kinematic pin grooves provided to the reticle-carrying container 3 and the kinematic pins provided to the light exposure apparatus. In addition, even if the reticle-carrying container 3 is set in wrong orientation in the system, the alignment device detects the misplacement and comes to a stop. After the stop, some measure is taken, such as changing the orientation of the reticle-carrying container 3.
In these cases, however, there is a problem of impartment of working efficiency. More specifically, if the reticle-carrying container 3 cannot be set into the system when it is wrongly oriented, the operator is required to exercise due care in placing the reticle-carrying container 3 in the system, which brings inefficiencies to his/her work. Moreover, in the case of the misplacement of the reticle-carrying container 3, the system is suspended all the while the alignment device comes to a stop and the reticle-carrying container 3 is re-oriented, resulting in the decreased efficiency of light exposure operation.